Medical care of individuals requires the widespread use of needles for taking blood samples, intravenous drug delivery, and the introduction or removal of other fluids via cannula, needles, or syringes. In the current context, the use of hypodermic needles to deliver plasma, anesthetics, or other medications has become commonplace in medicine, science, veterinary medicine, and biotechnology. The use of a hypodermic needle typically involves first inserting a needle into the patient, injecting a substance or withdrawing a substance as required, and then removing the needle from the patient. In most applications, the withdrawn and contaminated needle must be handled very carefully during disposal to avoid needle stick injury.
To help prevent health care workers from becoming injured, guards have been developed to block the tip of these needles after use. Indeed, needle stick protection for medical professionals has become of particular importance in recent years because of the prevalence of potentially fatal infectious diseases, such as, for example, Acquired Immune Deficiency Syndrome (AIDS) and hepatitis, that can be transmitted by the exchange of bodily fluids through inadvertent wounds caused by accidental needle tip pricks after withdrawal from infected patients. Accordingly, many kinds of needle protection devices are available for providing post injection needle stick protection.
However, many of devices are cumbersome and interfere with a single-handed procedure, or require a conscious action by the operator to activate the needle shield, or require additional complicated pieces to attach a needle guard to the needle tip. Some needle guards require the user to reposition the hand to manually activate a second mechanism that then engages the needle guard, adding to the complexity of the design, manufacture and use of the hypodermic needle assembly. With other designs, it is possible for a user to accidentally insert a finger into the open distal end of the needle guard sleeve and thus come into contact with the contaminated needle tip. Other designs require that the user either slide or apply the needle shield to the tip of the needle by hand, significantly raising the risk of unintentional contact with the needle tip.
Accordingly, it is desirable to provide a device for injecting medication or withdrawing fluid wherein a contaminated needle is enclosed after use, which overcomes the aforementioned drawbacks. The needle enclosing device should be automatically activated immediately following the medication injection cycle requiring no further input from the operator.